• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.8
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• pp.172-177
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• 2014

We present on a threshold switching device based on AsGeTeSi material which is significantly improved by two $N_2$ processes: reactive $N_2$ during deposition, and $N_2$ plasma hardening. The introduction of N2 in the two-step processing enables a stackable and thermally stable device structure, is allowing integration of switch and memory devices for application in nano scale array circuits. Despite of its good threshold switching characteristics, AsTeGeSi-based switches have had key issues with reliability at a high temperature to apply resistive memory. This is usually due to a change in a Te concentration. However, our chalconitride switches(AsTeGeSiN) show high temperature stability as well as high current density over $1.1{\times}10^7A/cm^2$ at $30{\times}30(nm^2)$ celll. A cycling performance of the switch was over $10^8$ times. In addition, we demonstrated a memory cell consisted of 1 switch-1 resistor (1S-1R) stack structure using a TaOx resistance memory with the AsTeGeSiN select device.

• Journal of Acupuncture Research
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• v.28 no.2
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• pp.49-55
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• 2011

Objectives : This study was to develop programmable and rechargeable electronic moxibustion device as an interdisciplinary research focusing on traditional Korean medicine. Methods : This device deployed several advances on safety and conveniences with the advantage of programmable heat stimulation, heating material and recharging method. The gradient of heat stimulation was programmed with the reference of previous studies and own measurements. The heat curve reached its efficacious stimulus temperature after three minutes, and maintained until 13 minutes with $42^{\circ}C$. We also incorporated feedback from field hospital experiences with the help of hospital staffs. Results : This device can prevent damages from skin burn and fire accidents, and control the smoke, smell and residue of moxa itself. Conclusions : This study will contribute for the development and improvement of efficacious and safe treatment methods for the traditional Korean medicine.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.5
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• pp.578-583
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• 2012

The pharmacological therapies and whole body vibration as non-pharmacological therapies were known to have adverse side effects. Therefore, partial stimulation was suggested and its effects were evaluated. This study aimed to evaluate the site-specific effects of partial stimulator for treatment of osteoporosis induced by estrogen deficiency. Sixteen virginal Sprague-Dawley rats (12 weeks old) were divided into 2 groups(no stimulation, stimulation groups). All rats were ovariectomised to induce osteoporosis. After 3 weeks of operation, the right tibiae in rats of stimulation group (frequency: 10Hz, cycle: 1500, strain on bone surface: $2000{\mu}{\varepsilon}$) were stimulated perpendicularly at right tibia by using partial stimulator for 6 weeks (3days/week). The right tibiae in rats were scanned, before stimulation (0 week) and at 6 weeks after stimulation by using in-vivo micro computed tomography. For investigation of changes in morphological characteristics, structural parameters were measured and calculated. At 6 weeks the morphological characteristics (relative value) in stimulation group were significantly enhanced than those in no stimulation group (p<0.05). In this study, we find that after 6 weeks of partial stimulation, the morphological characteristics of tibia trabecular bone were enhanced. Thus, we concluded that partial stimulation could be used to treat osteoporosis.

• Journal of Biomedical Engineering Research
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• v.31 no.5
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• pp.395-400
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• 2010

Hypertension is the chronic disease that the 16% of total population are suffering, and it needs to be studied to find alternative treatment because of the tolerance and side effect of medications that may bother some patients. in this paper, we verified practicality of implantable electrical stimulator that can readily change stimulus magnitude and frequency. And this device is possible to stimulate baroreflex or parasympathetic nerve. Therefore we performed in vitro tests and animal experiment for device's operating conditions. This device consist of implantable electrical stimulator and extracorporeal control/monitoring system. Stimulator was designed to make 1Hz~100Hz pulses and it can change continuous or periodic pulse train type. And this device can control stimulator's function and monitor stimulator's status and patients' blood pressure at exterior of body using ZigBee module as wireless telecommunication. We verified that stimulator have error rate under 5% at 50mm depth of organs and, stimulator makes high-efficiency energy with closer position of two electrodes. Also we can confirm the performance of device that decreasing blood pressure and heart rate of a rat by electrical stimulation.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.21 no.1
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• pp.60-65
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• 2007

The radiologic imaging device was implemented. It can be installed in an ambulance or used when an accident happens. After an equipment which generates X-ray generating unit with a tube in DC 12[V] had been made, a trait experiment using an oscilloscope was made. An experiment was carried out where the generated X-ray was saved as a form of a file using a digital detector. In this experiment, as a result of generating X-ray and detecting it using a digital detector, 1.67[MB]-, jpg- radical rays information could be saved. One distinct advantage of the developed radiologic imaging device is the fact that we can efficiently deal with emergency cases too far from the hospital, difficult to diagnose but treat simultaneously. By using the radiologic imaging device at the urgent scene of an accident or in a moving ambulance, we can provide the patient's X-ray information with the emergency medical specialist who is in the emergent medical center and have the patients prescribed and treated appropriately. As a result the developed emergency medical treatment can be expected.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.1-8
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• 2017

Fe-9.8Si-6.0Al mother alloy was manufactured using by Fe-3.5Si recycled scrap and Si powder. And then, soft magnetic alloy powder of $D_{50}$ size and sphere type were prepared by gas atomization process. To obtain the soft magnetic powder of a high aspect ratio, in the first, we conducted the ball milling process for 8 hours. And heat treatment was performed under $650^{\circ}C$, 2 hours and $N_2$ atmosphere condition for reducing the residual stress of the powder. Based on these process, we made around $50{\mu}m$ diameter Fe-9.8Si-6.0Al powder, which morphology and shape was a similar to the commercial Fe-Si-Al powder. Finally, the soft magnetic sheets were prepared by tape casting process using by those powders. The permeability of the tape casting sheet was measured, and we confirmed the possibility of reusing to the soft magnetic materials of Fe-Si electric sheet scrap.

• Journal of The Korean Society of Integrative Medicine
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• v.4 no.4
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• pp.41-51
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• 2016

PURPOSE : The purpose of this study was to identify whether 3D motion input device based mirror therapy could improve on upper extremity function, quality of life and depression in chronic stroke patients METHOD : Thirty six patients with chronic stroke were enrolled and randomly divided into three groups: 3D leapmotion mirror therapy group, mirror therapy group, and sham therapy group. 3D leapmotion mirror therapy group performed 3D motion input device based mirror therapy, mirror therapy group performed general mirror therapy, control group performed sham therapy. All patients received a total of 15 exercise session over a 5 week period (three times per week). Fugl-Meyer Assessment-upper extremity(FMA-UE), Stroke Specific-Quality of Life(SS-QOL), Beck Depression Inventory(BDI) were performed prior to and five weeks after the treatment RESULT : Subjects in the 3D leapmotion mirror therapy group showed significant improvements in upper extremity function, quality of life and depression following training. The changes of upper extremity function, quality of life and depression in the 3D leapmotion mirror therapy group were significantly more than them of the control group. CONCLUSION : The result of this study suggest that 3D motion input device based mirror therapy is an intervention to improve on upper extremity function, quality of life and depression in chronic stroke patients.

• Journal of the Semiconductor & Display Technology
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• v.19 no.3
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• pp.23-29
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• 2020

Electrochromic (EC) device is an element whose transmittance is changed by electrical energy. Coloring and decoloring states can be easily controlled and thus used in buildings and automobiles for energy saving. There exist several types of EC devices; EC using electrolytes, polymer dispersed liquid crystal (PDLC), and suspended particle device (SPD) using polarized molecules. However, these devices involve solutions such as electrolytes and liquid crystals, limiting their applications in high temperature environments. In this study, we have studied all-solid-state EC device based on Tin(IV) oxide (SnO₂). A coloring phase is achieved when electrons are accumulated in the ultraviolet (UV)-treated SnO₂ layer, whereas a decoloring mode is obtained when electrons are empty there. The UV treatment of SnO₂ layer brings in a number of localized states in the bandgap, which traps electrons near the conduction band. The SnO₂-based EC device shows a transmittance of 70.7% in the decoloring mode and 41% in the coloring mode at a voltage of 2.5 V. We have achieved a transmittance change as large as 29.7% at the wavelength of 550 nm. It also exhibits fast and stable driving characteristics, which have been demonstrated by the cyclic experiments of coloration and decoloration. It has also showed the memory effects induced by the insulating layer of titanium dioxide (TiO₂) and silicone (Si).

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.117-117
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• 2016

Total ankle replacement (TAR) is a visible option in the surgical treatment of degenerative or inflammatory diseases of ankle joint. it is attributed to the current TAR which has improvements in surgical technique, uncemented implant fixation and minimally constrained articulation. In the clinical result, they can show promised surgical result when compared to earlier attempts in TAR. However, TAR is still not as successful as total knee replacement (TKR) or total hip replacement (THR), it needs to be note that there are limitations in concerning of long term performance of TAR, the high failure rate still associated with wear of the PE (polyethylene) component that has related with their material property and surface roughness. The aim of this study was to introduce the tribology characteristics of total ankle joint prosthesis with one of TDR model which was fabricated to try multi-axis wear test as a region of motion in ankle joint. The wear specimen of TDR was prepared with Ti-6Al-4V alloy and UHMWPE (ultra-high molecular weight polyethylene) for tibia-talus and bearing component, respectively. A wear test was carried out using a Force 5 (AMTI, Massachusetts, US) wear simulator which can be allowed to move in three axis to flexion-extension ($+3^{\circ}{\sim}-6^{\circ}$), internal-external axial rotation (${\pm}5^{\circ}$), as well as sinusoidal compressive load (1.6 kN, R=10). All tests were performed following standard ISO 14243, wear rate was calculated with weight loss of UHMWPE bearing while the specimen has tested at certain cycles. As based on the preliminary results, wear rate of UHMWPE bearing was $7.9{\times}10^{-6}mg/cycles$ ($R^2=0.86$), calculated loss weight until $10^7cycles$ was 79 mg, respectively.

• Bulletin of the Korean Chemical Society
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• v.30 no.11
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• pp.2589-2594
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• 2009

Aging phenomena of plasma polymer films were studied by using the surface analysis techniques of contact angle measurement, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOFSIMS), and atomic force microscopy (AFM). The polymer films were grown on an aluminum substrate by using a plasma polymerization method from a gas mixture of acetylene and helium, and the films were subsequently modified to have a hydrophilic surface by oxygen plasma treatment. Aging of the polymer films was examined by exposing the samples to water and air environments. The aging process increased the hydrophobicity of the surface, as revealed by an increase in the advancing contact angle of water. XPS analysis showed that the population of oxygen-containing polar groups increased due to the uptake of oxygen during the aging, whereas TOF-SIMS analysis revealed a decrease in the polar group population in the uppermost surface layer. The results suggest that the change in surface property from hydrophilic to hydrophobic nature results from the restructuring of polymer chains near the surface, rather than compositional change of the surface. Oxidative degradation may enhance the mobility and the restructuring process of polymer chains.